Jejunal perfusion of simple and conjugated folates in tropical sprue.
Jejunal perfusion of simple and conjugated folates in tropical sprue.
复制标题
热带口炎性腹泻中简单叶酸和结合叶酸的空肠灌注。
DOI：
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发表时间：
1976
影响因子：
15.9
通讯作者：
C. Halsted
中科院分区：
文献类型：
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作者：
J. Corcino;A. Reisenauer;C. Halsted
在6名热带口炎性腹泻患者治疗前和治疗6个月后，利用空肠灌注和尿液回收技术，评估了标记的简单3 '，5'，9 '-（3）H蝶酰单谷氨酸盐（[（3）H]PG-1）和结合蝶酰-μ [（14）C]谷氨酰-γ-六谷氨酸盐（[（14）C]PG-7）叶酸的吸收。用DEAE-纤维素柱层析法鉴定了灌流过程中[（14）C]PG-7的降解产物。测定每例患者空肠粘膜叶酸结合酶、乳糖酶、蔗糖酶和麦芽糖酶的活性。所有未治疗的患者均发现[（3）H]PG-1和[（14）C]PG-7吸收不良，治疗后明显改善。（3）H和（14）C的尿排泄与这两种同位素的管腔消失有关。在灌注过程中获得的[（14）C]PG-7的管腔内降解产物的色谱图与以前在正常受试者中发现的没有差异，并且在治疗前后进行的研究中相似。与治疗后水平相比，未治疗患者的粘膜中叶酸缀合酶的活性增加，而粘膜乳糖酶、蔗糖酶和麦芽糖酶的活性最初较低，治疗后显著增加。这些观察结果表明，叶酸共轭酶起源于不同的粘膜位点比刷状缘dispensidases，并与以前的证据，叶酸共轭酶是一种细胞内酶是一致的。目前的研究已经证实了热带口炎性腹泻中简单叶酸和结合叶酸的明确吸收不良。在热带口炎性腹泻中，叶酸吸收不良是叶酸转运受损而不是水解受损的反映。
Absorption of labeled simple 3',5',9'-(3)H pteroylmonoglutamate, ([(3)H]PG-1) and conjugated pteroyl-mu[(14)C]glutamyl-gamma-hexaglutamate, ([(14)C]PG-7) folates was assessed in six patients with tropical sprue, before and after 6 mo of treatment, utilizing jejunal perfusion and urinary recovery techniques. Degradation products of [(14)C]PG-7 which were produced during perfusion were identified by DEAE-cellulose column chromatography. Jejunal mucosal activities of folate conjugase, lactase, sucrase, and maltase were measured in every patient. Malabsorption of both [(3)H]PG-1 and [(14)C]PG-7 was found in every untreated patient, with significant improvement after therapy. The urinary excretion of (3)H and (14)C paralleled the luminal disappearance of both isotopes. The chromatographic patterns of intraluminal degradation products of [(14)C]PG-7 obtained during perfusion did not differ from those previously found in normal subjects and were similar in studies performed before and after treatment. The activity of folate conjugase was increased in the mucosa of the untreated patients when compared to the post-treatment levels while the activities of mucosal lactase, sucrase, and maltase were originally low and increased significantly after therapy. These observations suggest that folate conjugase originates at a different mucosal locus than the brush border disaccharidases, and are consistent with previous evidence that folate conjugase is an intracellular enzyme. The present studies have demonstrated unequivocal malabsorption of both simple and conjugated folates in tropical sprue. In tropical sprue, folate malabsorption is the reflection of impaired folate transport and not of impaired hydrolysis.